In a new study, a team of scientists used purple onion peel dye to create a film that protects UV radiation solar cells with 99.9% effectiveness. New material can improve the durability of these cells and make solar energy more sustainable.
Solar cells often degrade due to exposure to ultraviolet (UV) radiation.
In a new study, a team of scientists has now reached a Effectiveness of 99.9% In the protection of solar cells against this radiation, thanks to a common vegetable, present in any kitchen: the purple onion.
According to the authors, whose results were presented in an article recently published in the Journal Applied Optical Materials, o Purple onion peel dye It may be the missing ingredient to reinforce the ultraviolet protection of solar cells.
Normally, the Solar cells are coated with an oil -based film for degradation induced by UV rays. These films include Petroleum derived materialssuch as the PVF fluoropolymer (polyvinyl fluoride) and the pet (polyethylene tereftalato).
In search of more sustainable and biological alternativesNanocellulose emerged as one of the main candidates. These nanostructures of cellulose, with particles less than 100 nanometers, are obtained from vegetable materialsand produced through the decomposition of cellulose in nanometric scale fibers.
The study authors found that the combination of nanocellulose with a dye extracted from the peel of the purple onion provided “a very effective UV protection”.
The study allowed to conclude that a protective film produced with this material eliminated 99.9% of UV radiation up to a wavelength of 400 nanometers. The protection achieved with the purple onion filter overcame that obtained with a PET -based commercial UV filter currently available on the market.
This result represents a “promising option in applications where protective material must have biological origin,” he said Rustem nizamovresearcher at the University of Turku, Finland, and first author of the study, in.
Essential commitments
In the study, the researchers compared the durability of four protective films made from cellulose nanofibers, explains the. These were treated with purple onion extract, lignin – a polymer present on the walls of some plant cells – and iron ions.
Although all have provided proper protection against UV radiation, the option with Purple onion dye turned to the most effective.
The solar cells face a critical commitment: UV radiation below 400 nm is harmful, but the transmission of visible light – wavelengths between 700 and 1,200 nm – is essential for the cell to transform radiation into electricity.
Thus, the development of a material that protects the solar cell and at the same time facilitates energy absorption is critical. THE ligninafor example, it has a dark brown color, which “limits its use in transparent films”Say the authors of the study.
“A Transmittance of these films With lignin is usually 50% between 400 and 600 nm and at most 85% above 600 nm, ”the investigators added.
In comparison, the nanocellulose film treated with purple onion dye overcame 80% light transmission In longer wavelengths (between 650 and 1,100 nm), maintaining performance over a prolonged period of testing.
The test period has evaluated the durability and performance of the filters when exposed to artificial light for 1,000 hours – The equivalent of approximately one year of sunlight in a climate of central Europe.
Nizamov highlights that this rehearsal period “evidenced the importance” of long -term testing for UV filters. “UV protection and light transmission of other biological base filters changed significantly Over time, ”he explained.“ For example, the iron -treated films presented initially a good transmittance, which has been reduced after aging. ”
Nizamov adds that the study has Extended Implications for various types of solar cells, in particular those of perovskite and organic photovoltaicsas well as in other industries where it is necessary to resort to biological base filters.
